This invention relates to a pin-type, key operated lock, and more specificially, to such a lock having at least one, and preferably both, of the cylinder and plug thereof continuously axially split and with the separation split thereof passing through an extreme side edge of each of the axially aligned pin holes. Thus, although one or both of the cylinder and plug are formed in this unique manner, once assembled into the pin-type key operated lock, they will operate in the usual manner and will be serviceable over a long period of useful life.
Most prior constructions of pin-type, key operated locks have had the cylinders and plugs thereof formed of individual single pieces, whether molded or otherwise fabricated, and then have had the necessary pin openings formed therein, as well as the key slots thereof. Obviously, the forming of the pin holes is a very exacting operation and relatively difficult to accomplish. Furthermore, it must be kept in mind that the cylinder pin holes must exactly properly align with the plug pin holes for proper operation of the ultimate lock.
One of the greatest difficulties encountered in forming these prior lock cylinders and plugs with their various aligned pin holes has been the formation of the pin holes between the cylinders and plugs with the exact alignment thereof while still accomplishing the same at reasonable production speed. These pin holes are extremely small in diameter and for many reasons a fair percentage thereof tend to lead off from their desired paths during the formation thereof. Thus, a relatively large percentage of scrap pieces are generated which otherwise would be proper lock parts.
There have been some prior attempts to form lock cylinders and/or plugs of axially split halves usually by die casting or forging. In all cases, the particular cylinder or plug has been formed by diametrically axially splitting the cylinder or plug exactly through the centers of the pin holes and then assembling the same into the final cylinder or plug. However, proper alignment of pin holes still provides an extreme problem and both halves of the cylinder or plug must be carefully formed and machined in order to accomplish the finally desired pin holes.